Double Michael addition/aza-cyclization: a valuable sequence for the construction of symmetrical and unsymmetrical spirobarbiturate-pyridines

Abstract A simple one-pot procedure for the preparation of symmetrical bis-hydrazone functionalized barbiturates, and a step-by step sequence for the synthesis of analogous unsymmetrical derivatives were developed. Their treatment in acid conditions furnish the symmetrical- and unsymmetrical-spirobarbiturate-pyridines, respectively.